Over a million minimally invasive procedures to preserve blood flow - angioplasties, stent placements, thrombectomies - are performed each year in the United States. The goal of this program is to provide means of measuring blood flow in these vessels during and after these procedures, something now not possible. We have developed a new blood-flow measuring component that can be integrated into minimally invasive interventional devices. During the procedure, it provides quantitative feedback to the operator on success in restoring blood flow;after the procedure, it can be remain as an indwelling lead to measure blood flow post-operatively. Its low power requirement also makes it suitable for long-term implantable use -- a small implanted unit, like a pacemaker, can monitor flow and wirelessly communicate an alert when declining blood flow demands intervention. This intravascular blood-flow measuring device is a newly developed, unique ultrasound transducer system. The design utilizes the principle of diffraction-grating transducers, which have been proven to measure blood flow accurately. A special configuration has been invented to make the transducer suitable for intravascular use: the electrodes on this transducer are wound around a rod, in helices, like a screw thread. This design has several advantages: it allows piezoplastics to be used at high frequencies, leading to low power requirements;use of piezoplastics makes a light, flexible device possible;it is easy to connect to;and, importantly, it is inexpensive to fabricate. Phase I of this project is to prove the concept by fabricating these transducers and demonstrating their capabilities in test phantoms, followed by placing one by minimally invasive means in a living animal and demonstrating successful blood flow measurement. PUBLIC HEALTH RELEVANCE: The goal of this program is to develop an intravascular device to measure blood flow during and after operations that improve or restore blood flow. By monitoring blood flow and alerting caregivers to a problem, it can prevent the serious consequences of too little flow of blood.